1 files changed, 69 insertions, 0 deletions
diff --git a/lib/avb/libavb/avb_hashtree_descriptor.c b/lib/avb/libavb/avb_hashtree_descriptor.c
new file mode 100644
index 0000000..b961e47
--- /dev/null
+++ b/lib/avb/libavb/avb_hashtree_descriptor.c
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "avb_hashtree_descriptor.h"
+#include "avb_util.h"
+
+bool avb_hashtree_descriptor_validate_and_byteswap(
+    const AvbHashtreeDescriptor* src, AvbHashtreeDescriptor* dest) {
+  uint64_t expected_size;
+
+  avb_memcpy(dest, src, sizeof(AvbHashtreeDescriptor));
+
+  if (!avb_descriptor_validate_and_byteswap((const AvbDescriptor*)src,
+                                            (AvbDescriptor*)dest))
+    return false;
+
+  if (dest->parent_descriptor.tag != AVB_DESCRIPTOR_TAG_HASHTREE) {
+    avb_error("Invalid tag for hashtree descriptor.\n");
+    return false;
+  }
+
+  dest->dm_verity_version = avb_be32toh(dest->dm_verity_version);
+  dest->image_size = avb_be64toh(dest->image_size);
+  dest->tree_offset = avb_be64toh(dest->tree_offset);
+  dest->tree_size = avb_be64toh(dest->tree_size);
+  dest->data_block_size = avb_be32toh(dest->data_block_size);
+  dest->hash_block_size = avb_be32toh(dest->hash_block_size);
+  dest->fec_num_roots = avb_be32toh(dest->fec_num_roots);
+  dest->fec_offset = avb_be64toh(dest->fec_offset);
+  dest->fec_size = avb_be64toh(dest->fec_size);
+  dest->partition_name_len = avb_be32toh(dest->partition_name_len);
+  dest->salt_len = avb_be32toh(dest->salt_len);
+  dest->root_digest_len = avb_be32toh(dest->root_digest_len);
+
+  /* Check that partition_name, salt, and root_digest are fully contained. */
+  expected_size = sizeof(AvbHashtreeDescriptor) - sizeof(AvbDescriptor);
+  if (!avb_safe_add_to(&expected_size, dest->partition_name_len) ||
+      !avb_safe_add_to(&expected_size, dest->salt_len) ||
+      !avb_safe_add_to(&expected_size, dest->root_digest_len)) {
+    avb_error("Overflow while adding up sizes.\n");
+    return false;
+  }
+  if (expected_size > dest->parent_descriptor.num_bytes_following) {
+    avb_error("Descriptor payload size overflow.\n");
+    return false;
+  }
+  return true;
+}